Solar power towers are towers used to receive focused sunlight reflected by a plurality of movable mirrors, or heliostats, such as those located in a heliostat solar power plant. These towers oftentimes contain solar absorption media such as falling liquids, ceramic particles, or sand that can capture the reflected sunlight in the form of thermal energy. The thermal energy contained in the solar absorption media is then used to generate electricity. In many cases, the thermal energy contained in the solar absorption media is transferred to water to generate steam used to drive turbines which produce electricity resulting in cooled solar absorption media. The cooled solar absorption media is typically recycled for repeated exposure to the reflected sunlight in the solar power tower.
It has been found that dark ceramic particles tend to enhance solar energy absorption properties. However, it has also been found that as these dark particles are repeatedly exposed to elevated solar temperatures, which can exceed 500° C., they become lighter in color and as a result lose some of their solar absorption capacity. There is a need, therefore, for ceramic particles that can maintain their solar absorption capacity after repeated exposure to solar energy.